In a treating process for a workpiece such as a semiconductor wafer or the like, an ionizer is used for discharging the workpiece being electrostatically charged. The ionizer is constructed such that a positive electrode and a negative electrode are disposed in an electrode-attaching opening at a lower surface of a housing, and a positive pulsing high voltage is applied to the positive electrode and a negative pulsing high voltage is applied to the negative electrode, as shown, for example, in the patent document 1, and thereby a corona discharge is generated so as to generate a positive ion and a negative ion from both electrodes.
In this kind of ionizer, it is sometimes required that a sensor for measuring ion balance in a discharging area is attached to the ionizer, or a filter for preventing adhesion of dust to the electrode is attached to the aforementioned electrode-attaching opening, depending on a condition of use, an environment of use, or the like. Further, in a case that the aforementioned electrode is constructed to be freely attached and detached, in a cartridge-type manner, it is also sometimes necessary to attach a parts for drop-off prevention to the ionizer so that the electrode cartridge does not abruptly drop off from the aforementioned electrode-attaching opening by vibration, a shock, or the like.
However, in the hitherto known ionizer, in a case that various types of related parts such as that described above are extended afterward, the same cannot easily be attached to the ionizer. Further, even though these parts are only just attached to the ionizer, each of the parts has to be individually attached thereto by different method. Thereby, an attaching work is difficult and the parts cannot easily be attached to the ionizer.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2005-108829